The present invention relates to a self-heating or a self-cooling container.
There have been many proposals for self-heating or self-cooling beverage containers. WO 96/29255, for example, discloses a can having the same external dimensions and shape as conventional beverage cans, but having an indented base to define an external cavity in which means to cool or heat the contents of the can are received.
Heating or cooling of the contents of the can can be achieved by using two chemical reactants which are stable when separated, but which produce an exothermic reaction or an endothermic reaction when mixed. U.S. Pat. No. 5,626,022 shows just one example, from many, of an insert for a self-heating or self-cooling can which enables mixing of the reactants when required. This construction, as is common, utilises a breakable or pierceable barrier to separate the two reactants and spikes or other piercing means to break the barrier when their reaction is required to heat or cool the can.
As indicated, self-heating containers may utilise an exothermic reaction as the energy source to heat the contents of the container. Commonly the exothermic reaction uses water as one of the reactants and the reaction produces steam and heated air. To date, that steam and hot air has simply been allowed to escape from the container. This escape is wasteful of the thermal energy which has been developed by the reaction and also presents a potential hazard to the user of the container.
The present invention seeks to reduce the problem with existing proposals discussed above.
According to a first aspect of the present invention there is provided a self-heating or self-cooling container having a tubular peripheral wall within which an internal cavity is defined, a first end member closing one end of the internal cavity, and a second end member closing the other end of the internal cavity, wherein a heating or cooling mechanism is supported by or incorporated within the peripheral wall, the container further comprising a sleeve arranged externally around at least part of the peripheral wall, and the container being arranged and constructed such that vapour generated by said heating or cooling mechanism is guided between the sleeve and said peripheral wall.
With a self-heating or self-cooling container of an embodiment of the invention, vapour produced by the heating or cooling mechanism, for example, a high pressure gas vented by a cooling mechanism, or the steam and/or hot air produced by an exothermic heating reaction, is guided between the sleeve and the wall of the container. This protects the user of the container and also enables the vapour to enhance the heating or cooling process. Thus, where the vapour is generated by a reaction arranged to heat the contents of the can and is therefore hot, the vapour, such as steam, is passed between the sleeve and the peripheral wall to provide a further heating effect to the contents of the container.
Preferably, the sleeve is absorbent such that the vapour is absorbed therein. Additionally and or alternatively, the sleeve is thermally insulating whereby the sleeve continues to protect the user from the heat or cool of the container, for example, if the user handles the container.
It will be appreciated that a self-heating or a self-cooling container of an embodiment of the invention may incorporate any heating or cooling mechanism. Various arrangements are described, for example, in WO96/29255. In a preferred embodiment, the heating or cooling mechanism comprises a first chemical reactant and a second chemical reactant received within an external cavity of the container defined, for example, by the second end member. The chemical reactants are kept apart until heating or cooling of the contents of the container is required.
Preferably, the longitudinal extent of the sleeve is the same or similar to the longitudinal extent of the peripheral wall.
In an embodiment, the internal surface of said sleeve and/or the external surface of the peripheral wall is channelled or grooved to guide the vapour along the external surface of the peripheral wall.
The sleeve preferably comprises an absorbent material.
In one advantageous embodiment, the sleeve is comprised of, or incorporates, a sleeve of cardboard, the internal surface of said cardboard sleeve being corrugated.
Preferably, the external surface of the sleeve is made of an impermeable material.
For example, the sleeve may have a layered or laminated construction, and in this case a layer of an absorbent material may define the internal surface of the sleeve, and a layer of an impermeable material may define the external surface of the sleeve.
Alternatively, the sleeve may comprise at least a first sleeve of an absorbent material arranged around said peripheral wall, and a second sleeve of an impermeable material arranged around said first sleeve.
In a preferred embodiment, the internal surface of the sleeve is made of an absorbent non-woven material, and the external surface of said sleeve is made of a plastics material with structural rigidity. For example, the plastics material is expanded polystyrene.
Such a sleeve construction is preferably made from a single web of material constructed by laminating a layer of any non-woven material, which is preferably absorbent, with a facing of expanded polystyrene. The polystyrene facing insulates a user from the heat or cold of the container contents and provides structural rigidity to the sleeve.
The external surface of the sleeve may be printed to act as a label and/or to add colour and design to the exterior of the container.
In an embodiment, the container further comprises vapour guide means for guiding the vapour generated by said heating or cooling mechanism between the sleeve and said peripheral wall, said vapour guide means comprising channels and/or grooves for the vapour defined by or in the peripheral wall and/or by or in the second end member.
Preferably, the second end member is incorporated, at least in part, in said heating or cooling mechanism, wherein vapour generated is arranged to exit from an external periphery of said second end member, and wherein said sleeve is arranged contiguous to the external periphery of said second end member.
For example, grooves and/or channels may be provided in said second end member to guide vapour to the external periphery thereof.
In a preferred embodiment, the internal cavity is for receiving the contents of the container, and the second end member comprises a base member which is indented to define an external cavity which extends within the peripheral wall but is separated from the internal cavity, said second end member further comprising a closure of said external cavity, said closure having operating means to actuate said heating or cooling mechanism
An example of such a construction is described in copending International application No. PCT/GB99/04241.
Preferably, the closure is provided with a peripheral rim which is appropriately shaped to clip onto the peripheral wall to close the external cavity.
In an embodiment, both the peripheral wall and said closure have a substantially circular periphery, and the closure has an annular peripheral rim which defines an annular groove receiving an edge of the peripheral wall.
In this respect, the container will generally have a circular cross-section, although the invention is applicable to containers of any shape.
Preferably, the operating means comprises a plunger affixed to said closure and upstanding therefrom. For example, the plunger may be integrally formed with the closure. In an embodiment, the plunger is mounted on the closure by way of a button formed in the closure.